With rapid development of mobile terminals, such as cellphone, hand-held computer, they have been widely used in various fields such as consumption, telecommunication, video and voice. Therefore, their standby time turns out to be a critical index for evaluate a product. The corresponding charging management chip must be power saving and function with low power consumption. Besides improving the process of the power management chip, optimizing and refining the circuit of the power management chip is also a development trend of low-power design. In related art, power saving management is implemented by adding various complex control logics. In the application of intelligent terminals, linear charging is gradually replaced by switch charging. Even if the power consumption has been reduced, the goal of zero power consumption cannot be achieved. Furthermore, other performances of the terminal may be influenced by the reduction of the power consumption.